Question 3

1. State two reasons for creating openings in walls.

1. State two advantages of timber formwork over steel formwork.

1. Explain the function of each of the following materials in relation to concrete

work:

1. aggregate;
2. cement;
3. water;
4. admixture.

Majority of the candidates were able to state the:

-           reasons for creating openings in walls;
-           advantages of timber formwork over steel formwork.

However, they were unable to state the function of each of the given concreting materials.

The expected response to question 3 is as given below:

1. Reasons for creating opening in wall

1. To provide a space for door.
2. To provide a space for window.
3. To meet ornamental/architectural design of building e.g. a circular hole specifically created in wall as design feature.
4. To create a space for installing air conditioner or fixing bracket fans.
5. To provide ventilation.
6. To provide illumination or daylight effect.

1. Advantages of Timber Formwork over Steel Formwork

It is:

-           easily cut into any desired shape;
-           readily available;
-           relatively cheap;
-           easily re-cycled.

1. Functions of concrete materials

(i)         Aggregate – This is a general term used to describe inert materials such as sand and stone which are binded together by cement paste to form a solid mass.

(ii)        Cement – This is a binding material in concrete/mortar.  It binds the particles of aggregate to form a solid mass.

(iii)       Water – When water is added to cement, the processes of hydration and setting will follow which will later lead to hardening process.  In addition, water performs the following functions:

            -           To damp the aggregate.
            -           To make the concrete workable so that it can be placed
                        easily and uniformly.
            -           It lubricates the aggregates.